Immigration agents will target Miami, Atlanta, Chicago, Baltimore, Denver, Houston, Los Angeles, New Orleans, New York City, and San Francisco. (John Moore/Getty Images/TNS) **FOR USE WITH THIS STORY ONLY*

NEW YORK — The promised White House crackdown on undocumented immigrants started early in Brooklyn.

U.S. Immigration and Customs Enforcement agents descended Saturday on a Sunset Park apartment building, ringing all the doorbells but eventually leaving empty-handed, eyewitnesses told the New York Daily News. President Donald Trump had promised a Sunday sweep by federal agents in New York and eight other cities across the country as part of his call to tighten the nation's borders.

"As they were leaving, we heard them say, 'We'll be back,'" said a woman who lived in the building. "I'm feeling sad because my young daughter was awake, and she heard the whole thing and was real scared."

The surprise ICE raid infuriated City Council member Carlos Menchaca, who represents the Brooklyn neighborhood.

"This is about whitening America," charged Menchaca, blasting Trump at a Manhattan news conference. "And this is coming from the top of government, by a white man. This is a white man saying our country needs to be white and it needs to be whiter and we need to remove the people of color."

Tensions were high across the city on the eve of the anticipated enforcement action. Sanctuary churches opened their doors to the undocumented, promising last-minute protection. Several immigrants told the Daily News they planned to go off the grid for a few days, staying with friends or moving from place to place to avoid arrest.

"We're not walking, sleeping, doing anything from normal life right now," said Shamin, a Bangladeshi man now living in Brooklyn. "Everybody's life is abnormal."

On the streets of Queens, the mere mention of the planned Sunday enforcement effort left locals silent and staring blankly down at the sidewalk. Fear was the overriding emotion among street vendors in Jackson Heights, even among those living here legitimately.

"People are afraid of this weekend — of course they are," said a Queens bodega owner, a U.S. citizen of Mexican descent who still declined to give his name. "Trump wants to fix the economy. But the backbone of the economy is us."

The doors were open wide Saturday at the Fourth Universalist Society Church, one of the city's sanctuary churches. The Rev. Schuyler Vogel said the number of undocumented immigrants seeking safe haven was growing as the hour drew near for the White House's promised sweep.

"I don't know how long the raids will go on, but people will stay as long as they need to stay," promised Vogel. "We were very aware that a lot of the people the government wants to deport are people who fled their own home country because they are in great risk."

New York officials offered free legal help and a telephone hotline as paranoia seized longtime city residents fearing sudden deportation. On a sunny July weekend perfect for a bike ride or the beach, many of the city’s undocumented immigrants instead cowered indoors.

"I'm very scared," said Abul, a 52-year-old native of Bangladesh and 27-year resident of the U.S. "I'm just living now here and there, not in my own house. There is no way to feel safe."

Abul's wife, daughter and son are all American citizens, and his spouse unsuccessfully petitioned for his citizenship when he spent 17 months in an Orange County, Calif., detention facility back in 2011-12. He's terrified of going back behind bars.

"My family was homeless and living in the street," he said. "I can't leave my family."

Even those already living in a sanctuary space were shaken by the anticipated wave of enforcement.

"To explain how I feel now, with these raids, bring up too much fear to talk about it," said one woman who found shelter inside a church.

City officials announced support from free legal counsel to a toll free hotline and distribution of "Know Your Rights" information sheets. According to the Pew Research Center, there are roughly 1.1 million undocumented people in the New York metropolitan area.

For many, though, anonymity is preferred over a legal battle — win, lose or draw in the courts.

"People are afraid ... we are staying inside (on Sunday)," said a 38-year-old undocumented Queens mother of a 5-year-old U.S. citizen. "There will not be as many people on the streets. I am fighting to stay here. But if they take me, what am I going to do?"

Rafael Ortiz, 29, a Mexican immigrant, said three of his friends were taken into custody by ICE before the promised sweep.

"ICE is always here," he said. "It's hard to prepare for something you don't know will happen."

Ravi Ragbir, executive director of the New Sanctuary Coalition, faces his own possible deportation to Trinidad. The activist was detained in January 2018 after making a scheduled appearance to meet with federal officials. His group plans to monitor any ICE raids while providing assistance to any undocumented immigrants in need.

"Normally, 100 people show up every week," said Ragbir. "Next week it will explode even more because people don't know what to do. We expect 500 (this) week."

A Jackson Heights, Queens, festival focused on getting the word out to South Asian immigrants now at risk of arrest. Visitors to the Chatpati Mela event were given "Know Your Rights" fliers, while speakers addressed the issue from the main stage every 30 minutes.

“A lot of people are afraid of what will happen this weekend,” said organizer Zohran Mamdani, 27. “This is a celebration. But we are also making sure people are aware of the justice that belongs to them.”